The primary objective of the BEST trial is to determine whether the addition of beta-blockers to standard therapy reduces the total mortality of patients with moderate to serve chronic congestive heart failure. The secondary objectives are to evaluate the effects of beta- adrenergic blockade on cardiovascular mortality, quality of life, hospitalization and costs, left ventricular ejection and more. In addition, it is planned to assess the impact of etiology, race and gender on the effect of treatment on primary and secondary outcomes.